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About the project
Smart City Rooftop Farming Graz is an urban farming project on the rooftop of the Science Tower in Graz, showing how to grow food in a sustainable way in urban spaces. The project pursues the goal to produce food, cool the temperature of the city, provide electricity, store rain water and to counteract surface sealing on the ground. The Science Tower is the first building in Austria, where the combination of these functions is realized.The Rooftop Garden grows fruits and vegetables on the 13th floor, 60 m above the ground, in the middle of Graz.
Increasing soil sealing, growing populations, resource-intensive supply – urban living spaces are facing challenges that require innovative and creative approaches. The project “Smart City Rooftop Farming” in Graz demonstrates a more efficient use of city roofs. The focus is on local food production with positive effects on microclimate, biodiversity and reduction of the carbon footprint within cities. Growing crops on roofs offers the opportunity to explore a better use of limited urban spaces in the future. The main goal of the project is to develop and establish food production close to consumers. Symbiotically, there are four additional functions combined here: food production, urban cooling, renewable energy production and social inclusion. With a wide range of stakeholders, it will create awareness for nature-based solutions and explore the economic and technical potentials for a climate-neutral future.
– Timely and comprehensive project planning, taking into account technical aspects and opportunities.
– The establishment of a stable stakeholder network is necessary to operate the garden economically.
– Considering differences between urban farming on rooftops and growing on the ground.
– The right choice of planting in terms of habitat, pollination and pest pressure.
– Appropriate substrate and adequate construction of the beds for optimal water supply and storage.
– Development of creative and local solutions for economic use.
80 tons of soil were lifted up the rooftop at 60m hight to produce food, around 800 kg on fruits, salates and vegetables are harvested per year.
Bees managed to reach the roof top as pollinators themselves; in addition, one colony of Bumblebees per year is setteled at the rooftop in spring.
The “Smart City Rooftop Farming” project, which opened in 2018, attempts to answer such essential questions as:
– How to make the best use of the limited settlement space, and:
– How to find a balance between rapid urban growth and a healthy and safe living space?
Rooftop Farming is located 60 meters above the ground on the roof of the “Science Tower”, an office building used as a research facility for urban and green technologies. The project includes 19 raised beds arranged in a ring. A special energy glass surrounds the growing area of about 100 m2. On the one hand, it generates green solar energy, and on the other hand, protects the plants from harsh weather and allows the necessary sunlight to come through for the optimal growth of herbs, vegetables and fruits.
An interdisciplinary team of experts from Joanneum Research – Life is coordinating and scientifically supporting the urban farming project. Together with partners from business, science, education and social sector, the project will help to develop and optimize the components necessary for the sustainable use of roofs for food production.
The design of the Science Tower included the Rooftop farming and the concrete planting beds were part of the construction process of the building from the beginning. However, the project manager did not have influence regarding the design and material used for the beds. Hence, the main challenges have a technical background:
(a) Characteristics of the building: The urban garden is located at a height of 60 meters and framed by energy glass. This means a restriction of aeration, which has the effect that some plant species develop less robustly. Selecting the appropriate plants that will thrive best in the given conditions is therefore essential. In this situation, there is also pest pressure. Since the entire project is purely biological, beneficial insects are part of a solution to this challenge. The shortage of bees and other pollinators at this altitude was solved naturally ¬¬– with the help of bumblebee colonies.
(b) Construction of the beds: The beds are made of concrete and most of them are only accessible from the front sides. This construction method is not optimal for daily cultivation. Involving experts at the planning stage would have solved this problem.
(c) Irrigation: Since the lack of drainage causes all rain to collect and accumulate inside the planting beds, the right soil composition had to be chosen at the initial stage of the project. The appropriate substrate, adapted to the specific conditions, is an important component for urban farming.
In the middle of a city the Rooftop Garden provides fruits and vegetables on the 13th floor, 60m above the ground on an office building. It is a case study which shows how farming can be brought back to urban spaces. It can be used as a best practice example to expand the concept of rooftop farming on other buildings and cities. It is a research lab to find out which plant species are adapted to this kind of farming and how this business model could be spread. About 120 different plant species can be found around the year on the rooftop. Employees working at the Science Tower can benefit from the harvest as well as a local restaurant, which sells food prepared with the vegetables of the Rooftop Garden.